Category Archives: Programming

Glide update: Tween overwriting

I’ve just added support for property overwriting to Glide, my Tweening engine for C#. This functionality exists in Actuate (a great Haxe library from which I’ve taken a lot of inspiration) and I’ve wanted it in Glide for a while now because it’s just so darn handy.

Imagine you start a tween off on its way:

…but then something changes, and now you want your image to travel instead to (X = 500) instead, and it should only take two seconds:

At first this will work fine, but when the second tween finishes, suddenly the first one takes precedence again and your image will keep moving towards (X = 100). You could cancel the first tween, but that would also cancel the movement towards (Y = 200).

Now, creating a new Tween on an object that’s already being tweened will cancel the movement of any properties that are currently being tracked. In the example above, the new X tween would overwrite the old one, the original Y tween would keep on working, and there’s no need to manually cancel anything.

The old behavior is still available; just pass false to the overwrite parameter. I’m pretty sure that won’t be necessary in the majority of cases, but it does exist if you want it.

Iridescence mobile development update

When I was at the Boston Festival of Indie Games with Iridescence, I’d tell anyone who asked about the mobile versions that they were about two or three weeks out. At the time I had every reason to believe that to be the case, but it turned out to be a little more complicated than I had anticipated.

This will be a moderately technical post, so the short version: Iridescence is still coming out on mobile devices (iOS, Android, and even Windows 8 phones), but it won’t be as soon as I had hoped.

Now onto the technical side of things.

Iridescence is written in Haxe, which is a language that aims to act as an intermediary between platforms. Instead of writing C++ for desktop platforms, Java for Android, Objective C for iOS, and C# for Windows phone, Haxe allows you to write in one language for all platforms, translating itself into the one that’s best supported by each target. On top of Haxe comes OpenFL, a framework that mimics the Flash API but has support for OpenGL and runs as a native application. A single codebase, a familiar API, and great performance? Almost sounds too good to be true.

It is.

A week before launch, I plugged in my Android tablet to get a build running. It had been my intention to have a tablet on the exhibition table so people could see the game running on a variety of platforms. I’d had it working in the past without any issues and without having to change a single line of code, so I expected it to be uneventful.

It wasn't.

It wasn’t.

I’m at a total loss to explain what’s going on. At first I thought it was just a matter of the renderer acting up, but the music doesn’t start either. Worse, I get this same behavior if the app is entirely empty. Other games work just fine, so it’s not a problem with the device. On my friend’s brand new Moto X nothing displays at all, so it’s not a matter of the tablet being below required specifications.

I’ve spoken to the OpenFL community and development team to no avail. A new beta version of the framework came out and had the same problem. Worst of all, I tried to roll back to an earlier version that had worked before and I couldn’t even compile. The OpenFL ecosystem is in a constant state of flux, with new build toolchains and dependencies popping up seemingly every time it updates, and the older (working) versions weren’t compatible with the new tools.

At this point it was time to start considering my options.

  • I could hunker down, wait for another OpenFL release, and hope that it would solve my problems.
  • Or I could bite the bullet and port the whole game back to C# (the language I wrote the original gamejam version in) and use Unity.

I’m choosing Unity. I’ll be using the Futile framework, partially because the API is Flash-inspired and will be easier to translate code between, but mainly because it’s a fully code-oriented workflow and only has support for 2D. When I first started working on the improved version of Iridescence Unity still didn’t have support for Linux and doing 2D work was a hassle. Not so any more. When I’m finished, this version will replace the current Windows/Mac/Linux Haxe-based one.

It’ll be a tough road but I’m ready to do what it takes. I leave you with the first step.

long road

Glide update: Structs don’t work that way

Glide has seen some modest adoption despite the fact that I’ve barely made any effort to get the word out. A handful of developers have contacted me thanking me for the project and asking for help, which I’m always glad to offer. One issue in particular has come up a few times recently, and it relates to the way .NET handles structs.

Structs are passed and returned by value, not reference. This means that when you assign an instance to a variable, that new variable has no relationship to the original object; any properties set on it will only apply to that variable. This is a problem in Glide, since I have to store a reference to the tween’s target object in order to apply the transformations. Worst of all, while normally this issue would be caught at compile time, it’s impossible to detect when you’re using reflection to set values, and the resulting behavior was that the operation would appear to silently fail.

Today I made some changes that should help users realize when they’re attempting to tween an incompatible type. Passing an instance of a struct to the tweener will result in a compile-time error, and if you sneakily box your variable into an Object it will throw an exception at runtime. This still doesn’t solve the problem of how to tween these types of properties, but I’ve got you covered on that front as well.

Glide already has support for extension classes that allow you to add specialized behavior for tweening your own types, but this feature wasn’t really documented anywhere. Now it is! I’ve added a wiki to the Glide Bitbucket repository with an example showing how to tween an XNA Vector2. It should be pretty simple to modify for your own needs…maybe a StringTyper extension that causes letters to show up over time like a typewriter, or a GlitchString that fills the whole string with garbage and slowly fills in the correct letters.

Gender interpolation in Flash

As a developer, I can’t help but deconstruct any game I end up playing. RPGs are a special fascination of mine, and I’ve often wondered how script writers handle games where the player can choose the main character’s gender. There are so many factors to consider beyond simply replacing occurrences of “his” with “her” and so forth; when you throw nicknames, honorifics, and insults into the mix along with all the various pronouns, there’s a huge number of variables to consider.

Today I was hanging out on the Flashpunk forums and the topic came up. Suddenly it occurred to me; you don’t need to have two defined lists of gender-appropriate tokens; just a consistent format for representing each possible option within the text itself.

For example, instead of doing this something like this:

Armitage: This is {var: player_name}. {gendered: subjective_uppercase}’s looking for a job.

The same could be written like this:

Armitage: This is {var: player_name}. {gendered: He/She}’s looking for a job.

It reads a lot better, for starters, and it avoids the need to maintain gendered tokens in a separate location than the script data. Granted, inline variables are harder to change in broad strokes at a later date, but on the other hand it’s harder to accidentally break lots of text by changing something global.

Here’s a little function I wrote to handle this in Flash. It’s not as flexible as the contrived example above, but it does what I set out to accomplish and I’m happy with it.

Let me know if this helps!

Stuck Scripting overhaul

Early on in the development of Slide (before Iridescence had come to be), I added support for small script files to allow levels to contain more complicated puzzles without running into false positives that caused the reset button to show up while the level was still perfectly solvable. I was using C# at the time, and options for proper scripting languages on the .NET platform are shamefully limited, so I rolled my own.

Here’s a sample of what it looked like:

The use-case for stuck scripts is extremely specific, so the language itself didn’t need too many bells and whistles. All I needed to do at any time was compare the number of game objects of a given color, and check if pawns had a valid path to their targets. The snippet above basically translates like so:

The puzzle is unsolvable if any of these are true:

there are more red pawns than blue
there are more green pawns than blue
there are more blue pawns than green, unless all blue pawns can reach a target
there are more blue pawns than red, unless all blue pawns can reach a target

Needless to say, it’s as ugly as it is functional, and adding new features proved difficult. The inflexibility of the original design meant for some truly impressive hijinks as I tried to implement more complex behaviors with only the original syntax.

Today I stripped the whole system out and replaced it with a new one. Since I’m using Haxe for this remake, I was able to take advantage of hscript, a subset of Haxe that allows for runtime interpretation. Now, the script above looks like this:

Much better.

The original scripting system was designed as a black box, with a minimal number of inputs and outputs. By keeping the interface consistent between implementations, I was able to completely change the underlying code without changing any other aspect of the program. It’s nice to be able to change something so integral to the gameplay without worrying about side effects.

Rotatable Graphiclists

Here’s a quick gif demonstrating a new feature I’m working on in #Punk, my C# port of Flashpunk.


Pictured: Two images (rectangle and circle), a Nineslice, and a Tilemap.

Since C# + SFML is so much more powerful than Flash, we can do some pretty cool things that weren’t previously possible. Rotatable Graphiclists are something I’ve wanted for a while, and they’re pretty close to being ready!

Glide update: From()

I made a small addition to Glide, my tweening library for C#. You can now specify starting positions for the variables you’re tweening, useful for when you need to change a variable instantly and then tween back to the default value. I use this when I’m making things flash for alerts or other important things for the player to notice.

Obviously you could just set the values manually before telling them to tween, but this is a nice shortcut if you’re setting a lot of them at once.

You can download Glide here.